1. Field of the Invention
The present invention relates to a method for harvesting and more particularly to a method for harvesting plants aligned in a plurality of substantially parallel rows, the rows being substantially evenly and closely spaced. The invention further relates to a method for converting conventional harvesting apparatus for such harvesting. The invention still further relates to an apparatus for harvesting from closely spaced, substantially parallel rows of plants.
2. Description of the Prior Art
The mechanization of harvesting operations has set certain limits on the varieties of plants which can be harvested, on the spacing of the plants to be harvested and on the time such plants can be harvested. In respect to such crops as cotton, mechanized harvesting has limited the proximity with which adjacent rows of the plants can be planted.
It is well known that the potential yield of cotton from plants grown in a given area is proportionate to the number of rows of plants able to be planted in that area. Thus, it follows that the more closely spaced the rows are, the higher the potential yield will be. However, it is believed that the optimum yield is obtained when the plants are aligned in rows having midlines, or centers, spaced about thirty inches from each other, whereby crowding of plants from adjacent rows is minimized and the unplanted aisles or paths between rows are discernible.
The advantage of closely planted rows of cotton can be fully exploited only if efficient methods for harvesting the cotton are utilized. The need for and use of mechanized harvesters to remove cotton from plants aligned in substantially evenly spaced rows has long been known.
Conventionally, two types of harvesters have been used for such purposes: "stripper" type harvesters and "spindle" type harvesters. While both of these conventional forms of mechanized harvesters perform adequately for their intended purposes, each type suffers drawbacks which limit its applicability in various harvesting situations.
The stripper type harvester can be constructed to pick cotton from rows of plants having midlines spaced as little as thirty inches apart. The more common forms of stripper type harvesters are the brush strippers and finger strippers, both of which are of fairly recent origin. While the use of these stripper type harvesters permits planting of the rows of cotton plants fairly closely to each other, with a concomitant increase in potential yield of cotton per acre, both stripper type harvesters are saddled with several serious limitations in their efficacy for performing their intended tasks.
For instance, the manner in which the brush stripper operates causes each cotton plant virtually completely to be defoliated, thereby picking a substantial portion of green bolls along with mature cotton. Thus, unless the bolls on each cotton plant in a given area evenly and substantially simultaneously mature, the actual yield of usable cotton from the area will be substantially less than the potential yield of the same area.
Another problem encountered with the brush stripper type harvester is that they tend to pick voluminous quantities of unwanted vegetative material, such as bracts, leaves, and small stems, together with the desired cotton. Thus, the subsequent ginning operations required to clean the cotton are made less efficient and more costly.
Another drawback of using the stripper type harvester is that the stripper mechanism has a tendency to jam and cease operation during harvesting of cotton due to the excessive amounts of trash gathered by the stripper mechanism. A related problem encountered with the stripper type harvester is that where rank growth of weeds and the like among the rows and between plants within rows is present, the stripper type harvester must travel very slowly to avoid constant jamming of the stripper mechanisms.
Yet another problem associated with the use of the stripper type harvester is that the stripper mechanisms have a marked tendency to jam and often stop completely when used to pick cotton that is damp from fog, dew or rain. Thus, it has long been known that the stripper type harvesters are beset by numerous drawbacks, and that therefore use of stripper type harvesters is neither the most advantageous nor the most efficient mechanized way to pick cotton.
The spindle type harvester has been known to those in the cotton industry as being a machine suffering few of the limitations presented by the stripper type harvesters. Conventionally, the spindle type harvesters have a frame or carriage borne on three wheels, two of which are deployed in spaced relation for power-driven rotation about a substantially common axis on the front portion of the carriage. The third wheel is mounted on the rear portion of the carriage and is rotatable about a pivotal axis, whereby the third wheel is employed for steering the harvester. A pair of picking heads are borne on the front portion of the carriage, spaced from each other a predetermined distance. The picking heads each have spindles adapted to engage cotton plants and remove cotton therefrom. The picking heads are conventionally spaced to permit the spindles to be brought into engagement with plants in adjacent rows, simultaneously to pick cotton from the plants of those rows.
However, the picking heads of spindle type harvesters have transverse dimensions which limit the degree to which the heads can be brought into proximity with each other, thereby also limiting the potential minimum distance the spindles can be spaced from each other. Thus, the minimum distance by which the rows of cotton plants to be picked by a spindle type harvester can be spaced from each other has heretofore been dictated primarily by the dimensional limitations of the picking heads. Conventionally, cotton plants planted in rows for picking by spindle type harvesters have had to be spaced with the midlines of the rows separated by a minimum of about thirty-eight inches, with a forty inch separation between midlines being more common.
However, spindle type harvesters exhibit few of the drawbacks associated with the stripper type harvesters; that is, the spindle type harvesters pick cotton which is relatively free of unwanted vegetation, immature boils, and other trash which would have to be removed during the ginning operation. Further, it has been found that cotton which is wet at the time of harvest is more readily picked using a spindle type harvester. However, while the spindle type harvester overcomes many of the disadvantages commonly associated with the stripper type harvester, for the reasons set forth above, it has heretofore been impossible to harvest cotton from rows of plants separated by a distance of less than about thirty-eight inches.
An additional factor adding to the desirability of planting cotton in rows having midlines spaced about thirty inches apart is that other crops such as green beans and milo are commonly spaced similarly; therefore, cultivating, spraying and other implements used for those crops can also be utilized without adjustment on the areas planted with cotton.
Therefore, it has long been known that it would be desirable to have a method for harvesting plants arranged in closely spaced rows, and particularly cotton plants planted in rows separated about thirty inches without simultaneously harvesting large quantities of extraneous materials that contaminate the cotton so harvested. It has further long been known that it would be desirable to have a method of converting a conventional spindle type harvester to enable such machine to harvest cotton from rows spaced more closely than were heretofore harvestable by such conventional machines. Finally, it has been known that it would be desirable to have a spindle type harvester adapted to pick such crops as cotton from rows spaced more closely than heretofore could be harvested by conventional spindle type harvesters.